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The-Hausdorff-dimension-of-the-survivor-set

Dynamical Systems 2026-04-28 v1

Abstract

Let 1<β<2 1<\beta< 2 , the sequence α(β)=α(β)1α(β)2\alpha(\beta)=\alpha(\beta)_1\alpha(\beta)_2\dotsb be the quasi-greedy β \beta -expansion of 1 1 , and t[0,1) t\in [0,1) be a bifurcation parameter. The β\beta-transformation is defined to be Tβ(x)=βx(mod1)T_{\beta}(x)=\beta x (mod 1) for x[0,1)x\in [0,1). The Hausdorff dimension of the survivor set K(t)={x[0,1) ⁣:Tβk(x)∉(0,t),k0}K(t)=\{x\in [0,1)\colon T_{\beta}^k(x)\not\in (0,t), \forall k\geq0\} is equal to lnλlnβ -\frac{\ln\lambda}{\ln\beta} under the condition that i=kα(β)iβit \sum_{i=k}^{\infty}\frac{\alpha(\beta)_i }{\beta^i}\geq t for any k1 k\geq 1 , where λ(0,1) \lambda\in (0,1) is the smallest positive solution of the equation n=1(α(β)ntn)xn=1\sum_{n=1}^{\infty}(\alpha(\beta)_n-t_n)x^n=1 with (tn)(t_n) being the quasi-greedy β\beta-expansion of tt. And the local H\"older exponent of the Hausdorff dimension function of K(t)K(t) is larger than the value of the function itself.

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Cite

@article{arxiv.2604.23737,
  title  = {The-Hausdorff-dimension-of-the-survivor-set},
  author = {Rui Kuang and Bing Li and Yuanfen Xiao},
  journal= {arXiv preprint arXiv:2604.23737},
  year   = {2026}
}

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15 pages